[Daryl]

I cannot understand the bio mechanics of why 80% of one's body weight should end up over the right foot as a result of the backswing pivot action movement.
Weight and Weight Transfer supply the energy for Hip Action. Hip Action moves the Shoulders.

Could you please explain the causal mechanical connection between a backswing hip action movement (cause) and body weight movement to the right foot (effect) that allows you to claim that 80% of body weight should end up over the right foot at the end-backswing position?
The Weight should not end up over the Right Foot. The Hips need only Turn during the Backstroke. The weight shifts (Direction of Force) to the instep of the Right Foot during the Backswing. The more weight that can be shifted/directed to the Right Foot, the more weight can be shifted to the Left foot during startdown. Shifting Weight supplies the energy behind Hip Action. The amount of weight determines the amount of energy-force created.

You also state that increased weight transfer increases the force that can be exerted by the downswing hip action move. On "what" is that force exerted?
If the Left Heel is raised (pulled) above the ground during the Backstroke Hip Turn, then the Left Hip lowers and the Right Hip Raises (Standard Knee Action). As the Left Heel is lowered to the ground during Startdown, the Left Knee Straightens and The Right Knee bends which Raises the Left Hip and Lowers the Right Hip. This can be performed with or without a shift in Weight. If without, then it’s simply a Hip Turn and allows Shoulder Rotation. But with a Weight Transfer, Hip Action is created because a Force has been generated to Throw the Right Shoulder Downplane. The more Weight Transfered, the greater the force. The Transfer moves weight from the Instep of the Right Foot to the Left Foot Heel. The more weight, then the more Left Leg Muscle used to straighten the Left Knee which increases force raising the Left Hip. The greater the force raising the Left Hip, then the Greater the force pulling the Right Shoulder Downplane. Keep in mind that at the Top of your Backswing, your Left Shoulder is as Low as it will ever be. You cannot force the left shoulder upward (with torso muscle because that doesn't force the club downward), but you can force the right shoulder downward. That's Hip Action. Otherwise, at startdown, you end up using torso muscle to spin the shoulders and pull on the arms. no-no.

You also state that hip action propels the hands to the low point without any upper body muscular effort. Could you please explain the bio mechanics of that phenomenon?
See Above. The force that propels the Power Package will not diminish until the Right Shoulder speed diminishes. Low Point, Straight Right Arm.

You also state that the hip action exerts more force than upper body/arm action. Are you claiming that this applies to the force exerted on the clubshaft or ball? If so, could you please explain the bio mechanical/physics mechanism.
Hip Action Forces are exerted on the Right Shoulder and Power Package and in turn on the Primary Lever and Ball and #3 pressure Point. Your Pivot supplies all of the force and effort in a Golf Swing (Swingers). Power Package transport should be performed entirely by the Pivot. The Power Package, including Left Wrist Cock will stay intact until release if Hip Action is used. Any pulling with the Arms or turning of the shoulders with torso muscle will cause immediate and premature throwout of the Secondary Lever. Some people can play this way but expend great effort and distance is erratic with all clubs.
An ever present question/mystery is how can a 120lb LPGA Player hit a Drive 250 yards. I believe that you don’t have to be strong enough to perform one push-up to hit a Golf Ball 250 yards.

Hip Action should be learned and Zone 1 should be mastered.